Current Sense Transformers: An Overview
Top tier OEMs and global contract manufacturers can strengthen relationships with customers by explaining how electrical current works for applications such as telecommunications and railway equipment. Current sensors and current sense transformers are key components to managing such large systems.
How Current is Measured and Monitored Two parameters that ideally account for current measurement are voltage drop and magnetic field generation. Factors that come into play include the angles of the current path and permeability, which measures how well conductivity of materials can generate magnetic fields.
Voltage drop can be measured across a resistor once a sense resistor is placed in series with the circuit. For moderate current, voltage divided by resistance in Ohms produces the value of current in amperes. A more appropriate way to measure smaller currents is focusing on vibration and pressure, using an I-V converter.
Current Sensors Current sensors can be customized for different industries. There are a variety of solutions for any given industry, so it's important to determine which method works best for your specific operation. Magnetic current sensing eliminates the need for direct contact with a monitored circuit, which is safer for measuring high-voltage currents.Related: Custom Toroidal Transformers: Should Cost Be a Hindrance?
Current Sense Transformers Current sense transformers are commonly used by companies that monitor, control and maintain electronic equipment in an isolated current environment. It is used only for AC and is similar to a magnetic current sensor, housing a toroid constructed with magnetic material.
Ideally, a current sense transformer has unlimited inductance, no winding resistances, accurate coupling and no parasitic capacitance. Current is in the primary and secondary windings, but secondary current is merely primary current divided by its ratio.
Unfortunately, current transformers are not widely understood, which can result in weak performance. The value of termination impedance and its related components can be adjusted to enhance accuracy and performance over a wide range of frequencies or pulses.
Allied Components International has been providing custom sense transformers to OEMs and contract manufacturers since 1992.